Question 1

Which of the following statements best explains why viruses cannot be grown on standard nutrient agar plates like bacteria?

Accepted Answer

Viruses lack the metabolic machinery to replicate independently and must infect living host cells to reproduce.

Question 2

Which of the following is NOT a step in Koch's postulates for establishing a causal relationship between a microorganism and a disease?

Accepted Answer

The microorganism must be genetically sequenced.

Question 3

A scientist is studying a virus with a single-stranded negative-sense RNA genome. Which enzyme must this virus carry to ensure successful replication in a host cell?

Accepted Answer

RNA transcriptase (RNA-dependent RNA polymerase)

Question 4

Which of the following best describes the structure and function of a viral capsid?

Accepted Answer

A protein shell composed of capsomeres that protects the viral nucleic acid and facilitates attachment to host cells.

Question 5

Which of the following viruses is most likely to integrate its genome into the host cell's DNA during replication?

Accepted Answer

A retrovirus

Question 6

A researcher uses a Chamberland filter to remove bacteria from a solution but finds that the solution still causes disease in plants. What does this observation most likely indicate?

Accepted Answer

The disease is caused by a virus, which is smaller than bacteria and passes through the filter.

Question 7

Which of the following statements about prions is TRUE?

Accepted Answer

Prions cause disease by inducing abnormal folding of normal cellular proteins.

Question 8

Which of the following best explains why enveloped animal viruses are often released from host cells by budding rather than cell lysis?

Accepted Answer

Budding allows the virus to acquire a portion of the host cell membrane, forming its envelope and enabling persistent infection.

Question 9

Which of the following is a key difference between the replication cycles of bacteriophages and animal viruses?

Accepted Answer

Animal viruses may require entry into the host cell nucleus for replication, while bacteriophages replicate in the cytoplasm.

Question 10

Which of the following best describes the role of oncogenes in cancer development?

Accepted Answer

Oncogenes promote uncontrolled cell division and can lead to tumor formation.

Question 11

A virus with a segmented genome composed of double-stranded RNA is most likely to require which of the following for replication?

Accepted Answer

Viral RNA-dependent RNA polymerase

Question 12

Which of the following is a characteristic unique to viroids compared to viruses?

Accepted Answer

Viroids are composed solely of circular RNA and lack a protein coat.

Question 13

Which of the following best explains why prion diseases are difficult to control in medical settings?

Accepted Answer

Prions are resistant to incineration and autoclaving, making them hard to eliminate.

Question 14

Which of the following best describes the function of viral surface proteins?

Accepted Answer

They mediate recognition and attachment to specific host cell receptors.

Question 15

A patient is infected with a virus that uses reverse transcriptase to replicate. Which of the following drugs would most likely inhibit this virus?

Accepted Answer

A reverse transcriptase inhibitor

Question 16

Which of the following best explains the concept of 'burst size' in the lytic cycle of bacteriophages?

Accepted Answer

The number of new phage particles released from a single lysed host cell.

Question 17

Which of the following is a real-world consequence of viroid infection in agriculture?

Accepted Answer

Viroids can lead to significant crop losses due to plant diseases.

Question 18

Which of the following best describes the difference between benign and malignant tumors?

Accepted Answer

Malignant tumors have the potential to metastasize, while benign tumors do not.

Question 19

Which of the following is a plausible reason why viruses are considered 'obligate intracellular parasites'?

Accepted Answer

Viruses require host cell machinery for replication and cannot reproduce outside living cells.

Viruses, Viroids, and Prions: Tiny but Deadly (Chapter 13 Study Notes)

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